MP5016 – 2.7 - 15V, 0.7 - 5A, PROGRAMMABLE, CURRENT-LIMITED SWITCH
To protect the downstream load when there is a
surge voltage at the input, the MP5016 provides
OPERATION
The MP5016 is designed to limit the inrush
current to the load when a circuit card is inserted
into a live backplane power source, thereby
limiting the backplane’s voltage drop and the
dV/dt of the voltage to the load. The MP5016
offers an integrated solution that monitors the
input voltage, output voltage, output current, and
die temperature, which eliminates the
requirement of an external current sense power
resistor, power MOSFET, and thermal sense
device.
an output OVP function. An accurate and fast
comparator monitors the over-voltage condition
of the output. If the output voltage rises above
the threshold set by MODE, the gate of the
internal MOSFETs is pulled down quickly and is
regulated to a certain value to keep the output
voltage clamped at the OVP threshold. The fast
loop response speed keeps the over-voltage
overshoot small.
Current Limit
The MP5016 provides a constant current limit,
and the current limit can be programmed by an
external resistor.
Under-Voltage Lockout (UVLO)
The MP5016 can be used in the 2.7V to 15V
input supply system. There are high-energy
transients during normal operation or hot swaps.
These transients depend on the parasitic
inductance and resistance of the wire and the
capacitor at the VCC node. If a power clamp
(TVS, Tranzorb) diode is not used, the E-fuse
must be able to withstand this transient voltage.
The MP5016 integrates a high-voltage MOSFET
with up to 15V of continuous voltage and 26V of
maximum transient input voltage. The MP5016
also uses a high-voltage circuit for the VCC node
to guarantee safe operation.
The desired current limit is a function of the
external current limit resistor and can be
approximated with Equation (2):
0.55(V)
ILIMIT(A)
3870
(2)
RLIMIT(Ω）
Where 3870 is the current sense ratio.
Once the current limit threshold is reached, the
internal circuit regulates the gate voltage to hold
the current in the power MOSFET constant. To
limit the current, the gate to the source voltage
must be regulated from 5V to around 1V. The
typical response time is about 15µs. During this
period, the output current may have a small
overshoot.
MODE
MODE is used to select the output over-voltage
protection (OVP) threshold.
Three digital inputs are provided for MODE.
Drive MODE high to VCC to set the output OVP
clamp voltage at 15.2V. Drive MODE low to GND
to set the output OVP clamp voltage at 5.75V.
Float MODE for no OVP clamp protection. The
OVP threshold can be set by connecting a
resistor from MODE to ground. For more details,
refer to the Application Information section on
page 14.
If the current limit condition lasts longer than 2ms,
the IC enters hiccup mode with 2ms of on time
and 700ms of off time.
The MP5016 allows ILIMIT to be floated during
operation. If ILIMIT is floating, the current limit is
set at a fixed 2.5A internally.
When shorting ILIMIT to GND, the normal
current limit is disabled, but the secondary
current limit still works. The secondary current
limit is set to 8A internally. When the secondary
current limit is triggered, the IC shuts down the
power MOSFET.
Soft Start (SS)
The soft-start time is related to the dV/dt slew
rate and input voltage and can be calculated with
Equation (1):
Vin(V)
t_ss(ms)
(1)
dv/dt (V/ms)
The dV/dt slew rate is controlled by an external
DV/DT capacitor setting and the MODE setting.
Fast Output and Input OVP
MP5016 Rev.1.0
6/20/2017
www.MonolithicPower.com
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